The grief-stricken mother of a Dublin man who is believed to have been murdered has appealed to his killers and their families to let her know where he was hidden.

James Kenny McDonagh, 28, a van delivery man from Islandbridge, Dublin, was last seen driving his wine-coloured Mazda 626 at Bluebell in Dublin on October 27.

His car was found burning on waste group near Peamount Hospital. James kept horses in stables nearby and is believed to have been followed as he went to tend to them.

He was the only child of Jackie Kenny, who yesterday appealed to his killers or anyone who knew anything about what happened to him to either let her or gardai know where his body is.

Mrs Kenny said the pain of losing her only child was worsened by reports that he was caught up in one of the city's drug feuds. Her son, she said, lived with her and worked hard to make a living at his delivery business.

Gardai agreed with Mrs Kenny, pointing out that Mr McDonagh had no criminal convictions and only came to their attention for some minor road traffic offences.

Addressing her son's killers, Mrs Kenny said: "I am asking you as a parent to step back and just think what it is like to have lost your only child, not to know if he is dead or alive or where he lays at night and the dread of never seeing him again.

"Well, I can tell you it's a living nightmare. I know somebody out there knows of James's whereabouts and most likely what's happened to him.

"And all I ask of them is to please give my son back. Let me know where he is. I ask you to dig deep into your heart and help end this nightmare. Maybe somebody was involved that didn't want to be.

"I would appreciate if you could find a way to let me know where my son James is so that we can find closure. Just think that this could be your child some day. Nobody knows. If I could help find someone else's child I would. So, please can you help me find my only child James. I am lost without him."

Mrs Kenny said her family and friends have been a great comfort to her, but that she has had "no life" since her son disappeared.

She said she constantly waits by the phone thinking he will ring. She has been finding sleep difficult and lost her appetite. She said James's nine-year-old daughter, who he called "Princess", was also deeply affected.

He had been a horse enthusiast since childhood when he attended Chapelizod National School and then Palmerstown Secondary. "He always loved horses and was very good with them. One of his horses had a foal last year and it broke its leg and had to be put down. He was looking after its mother, going out to it all the time."

Mrs McDonagh said she and her family had been "devastated" by claims he was involved in serious crime and that his disappearance was linked to the murders of Ballyfermot brothers Paul and Kenneth Corbally. He had never been arrested or questioned about any murders and gardai had not called to the Kenny home.

The chief suspect in the disappearance and suspected murder is a figure long known to gardai as an extremely violent criminal.

He was also the chief suspect in the double murder of Darren Carey, 20, and Patrick Murray, 19, whose bodies were found in the Grand Canal at Karneystown, Co Kildare, in January 2000. They were murdered on the morning of New Year's Day after being lured to the spot by the killer and murdered because they had been arrested with a kilo of heroin at Dublin Airport belonging to the criminal.

The same man is also the main suspect in the murder of Dublin man Keith Ennis, 29, whose dismembered body was recovered from a canal outside Amsterdam in March 2009.

Gardai believe Mr Ennis was murdered because he was blamed for the loss of another consignment of drugs.

Gardai describe the killer as a "psychopath" who murders people he believes have either slighted him or because he suspects they might turn State's evidence against him. He also murders, they say, to instill fear in others around him.